Escape LOGNAME variable according to GCE rules

playbooks/gce/openshift-cluster/tasks/launch_instances.yml

@@ -13,7 +13,7 @@
 # unsupported in 1.9.+
     #service_account_permissions: "datastore,logging-write"
     tags:
-      - created-by-{{ lookup('env', 'LOGNAME') |default(cluster, true) }}
+      - created-by-{{ lookup('env', 'LOGNAME') | regex_replace('[^a-z0-9]+', '') | default(cluster, true) }}
       - environment-{{ cluster_env }}
       - clusterid-{{ cluster_id }}
       - host-type-{{ type }}